Hello,

New release:
http://download.gna.org/mhwaveedit/mhwaveedit-1.4.20.tar.bz2

What's new:

- This release fixes the ALSA problems that appeared with 1.4.19 that 
has been discussed on the mailing list.

- Manual page added.

Some tech details on the ALSA driver bug-fix:

The cause turned out to be that when the ALSA output device is opened in 
non-blocking mode, the function snd_pcm_writei in the ALSA library 
doesn't do partial writes when the output buffer is almost full, but 
instead it writes nothing and returns EAGAIN. So the driver got into a 
situation where ALSA keeps asking for more data but then refuses the 
data, over and over again.

Because of this bug, plus another bug in how the EAGAIN condition was 
handled in the driver, the ALSA playback stopped.

This bug didn't trigger on my hardware because it has a buffer size 
which is an even multiple of the write size that mhwaveedit uses.

I still don't fully understand why this bug didn't cause problems 
before, however it has probably caused peaks in CPU usage that people 
haven't noticed.

As part of the debugging effort, a large part of the Alsa driver was 
re-written and cleaned up. The code for setting buffer size was obscure 
and didn't do much good so now it always uses the maximum buffer size 
instead, and a period of 0.1 seconds if the buffer is large enough.

Best regards,
Magnus


_______________________________________________
Mhwaveedit-discuss mailing list
[email protected]
https://mail.gna.org/listinfo/mhwaveedit-discuss

Reply via email to